JPS63160848A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To easily remove the inoperative condition of an ink jet recorder due to the thickening or adherence of ink in the orifice by a method in which ink is introduced from a storage tank into the joint part in the discharge and- recovery treatment. CONSTITUTION:A head unit is positioned on a home position and covered with a cap 9, and a valve 12 is opened. Under the condition, when a pump 5 is operated for suction, ink 16 is sucked up from an orifice 14, and since the valve 12 is opened, the ink 16 is sucked up with air from an ink suction port 13 to keep the liquid level of ink in a subtank 15 constant. Even when the thickening or adherence of ink in the orifice 14 occurs without recovery of discharge by suction of the pump 5, thickened or adhered ink in or near the orifice 14 can be washed away since the cap 9 is filled with ink by suction from the suction port 13.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an inkjet recording device.

[Prior Art] Conventionally, this type of apparatus has an ejection opening (orifice) having a small diameter, usually about φ30 to 100 μm, for ejecting recording droplets.

Therefore, in this type of device, if left at room temperature or high temperature for a long period of time, the moisture in the recording liquid (ink) will evaporate, easily increasing the viscosity of the ink near the orifice, or causing the ink to stick, resulting in the formation of recording droplets. may become impossible.

Therefore, in conventional devices, the orifice section is capped when not in operation to prevent ink from evaporating from the orifice, and ink is forcibly sucked from the orifice section when recording droplets are not ejected. Some have a mechanism.

[Problems to be Solved by the Invention] However, even with conventional devices that have taken such measures, problems occur especially when left in a high-temperature environment for a long period of time, or when special inks with high fixing properties and low bleeding rates are used. In some cases, it may not be possible to adequately deal with thickening or sticking of the ink at the orifice.

[Means for Solving the Problems] The present invention solves these problems by simplifying the structure and making it possible to easily eliminate the inoperable state of the device due to ink thickening or sticking at the orifice. An object of the present invention is to provide an inkjet recording device that improves the reliability of the device after being left at high temperature or room temperature for a long period of time, and also allows a wide range of recording inks to be selected.

Therefore, the present invention includes an ejection port that ejects ink onto a recording medium, a storage member that stores ink to be supplied to the ejection port, and an ejection recovery that discharges ink from the ejection port and introduces ink from the storage member. and a discharge port that can be joined to the discharge port during discharge recovery processing by the discharge recovery means;
It is characterized by comprising a joining member having a first part that receives the ink discharged from the ejection port during the joining, and a second part that receives the ink introduced from the storage member by the ejection recovery means.

[Operation] That is, according to the present invention, during the ejection recovery process, ink is introduced into the joint member from the storage member and the vicinity of the ejection port is washed, so even if there is thickened or fixed ink at the ejection port, You can definitely remove this.

[Example] The present invention will be described in detail below with reference to the drawings.

1 and 2 illustrate a first embodiment of the present invention, and FIG. 1 shows an inkjet recording apparatus to which the present invention is applied.

In the same figure, the reference numeral 1 indicates an inkjet recording head according to the present embodiment and a head unit having a sub-tank for temporarily storing ink. The liquid is ejected as droplets and recorded on the recording paper 4.

Also, the reference numeral 5 is a discharge recovery pump that is used when droplet discharge failure or non-discharge occurs, and this pump 5
The ejection operation is restored by suctioning the liquid through the ink suction port provided in the cap 9 which communicates with the orifice provided in the head of the head unit 1 and the sub-tank via the suction tube 6. Then, the sucked ink is led to a waste liquid reservoir 8 and stored.

Note that the cap 9 is disposed outside the recording area, for example at a home position, so as to be able to face the head unit 1, so that when inkjet recording is not performed for a long period of time or when the apparatus is transported, the ink inside the head unit 1 may dry. It is used to prevent foreign matter such as dust from getting mixed into the ink, and is moved in the direction C in the figure and joined to the tip of the head unit 1.

Also, the reference numeral 1O is a key ridge on which the head unit 1 is mounted and is scanned in the S direction in the figure, and the reference numeral 11 is a platen that transports the recording paper 4 in the f direction in the figure while regulating the recording surface by the head unit 1. It is.

FIG. 2 shows a cross section of the inkjet recording apparatus shown in FIG. 1 when the head unit 1 is positioned at the home position facing the cap 9. As shown in FIG.

In the figure, reference numeral 14 indicates an orifice formed at the tip of the ink flow path 17, and the ink 16 supplied through the ink flow path 17 is ejected from this orifice 12 as flying droplets.

18 is a cylindrical piezoelectric element, which is connected to the ink flow path 1.
7 so as to surround the ink flow path 17,
Generates energy to form flying droplets.

Reference numeral 15 is a sub-tank that temporarily stores the ink supplied by the ink tank 2, and when the cap 9 is closed, suction is performed by the pump 5 shown in FIG. 1 through the suction tube 7. , the liquid level in the sub-tank 15 is kept constant. The suction tube 7 is an ink suction port 1 provided in the sub tank 15 and the cap 9.
3, and a valve 12 is provided in the middle.

FIG. 3 shows an example of the configuration of the control system of the device according to this embodiment. 200 is a control unit in the form of a microcomputer having, for example, a CPU, ROM, RAM, etc., and controls each unit according to the processing procedure shown in FIG. 4 stored in the ROM,
A PS that drives the piezoelectric element 18 of the head unit 1 to record image data received from a host device, etc.
is a paper sensor that detects the recording paper P, and in response to the detection, the control unit 200 controls the paper feeding mechanism 11 including the paper feeding motor.
The platen roller 11 is driven via A to control paper feeding. C5 is a carriage position sensor, and the control unit 200 controls the carriage motor I according to the detected position information.
The drive of the carriage lO and the positioning to the home position etc. are controlled via the OA.

9A indicates the transmission mechanism such as gears and cams, and the cap 9 is C in Fig. 1.
This is a transport mechanism that has a driving member such as a motor for transporting in the direction. Reference numerals 1205 and 1255 indicate command means and display means, respectively, provided on an operation panel (not shown).

FIG. 4 shows an example of a recording processing procedure according to this embodiment.

First, when the power is turned on, this procedure is started, the valve 12 is closed in step S1, the head unit 1 is positioned at the home position in step S3, and capped with the cap 9, and the process proceeds to step S5. and goes into standby mode. That is, in the standby state, the orifice 14 is capped and sealed to prevent moisture in the ink from evaporating, thereby preventing ejection failure due to ink thickening or sticking. Note that at this time, the valve 12 may be in an open state.

When image data is input from the host device in this standby state, the cap 9 is opened in step S7, and recording processing is performed in step S9. During this recording process, that is, when the cap 9 is open, the valve 12 is closed to prevent the liquid level in the sub-tank 15 from dropping.

Next, the recording state is determined in step 511, and if the recording state is good, the process proceeds to step S3 and to a standby state in step S5. The recording state can be determined visually or by a recording defect detection device provided separately, and if a recording defect has occurred, recovery operations from step 513 onwards are performed.

After the head unit 1 is positioned at the home position in step 513 and capped with the cap 9, the valve 12 is opened in step 515. In this state, when the pump 5 is driven to perform suction in step 517, the ink 16 is suctioned from the orifice 14, and since the valve 12 is open, air and ink are suctioned from the ink suction port 13, and the sub tank The ink liquid level in 15 is kept constant. The pump 5 may be driven by a command from the control unit 200 as shown in the third figure, or may be driven manually.

Here, even if the ink in the orifice 14 increases or sticks and the ejection cannot be recovered by the suction force of the pump 5 alone, the configuration according to this example allows the ink to be suctioned from the suction port 13. Since the cap 9 is filled with ink, thickened or stuck ink near the orifice 14 can be washed away.

After this bombing is completed, test recording is performed in steps 519 to 525. That is, the valve 12 is closed again in step 519, the cap is opened in step S21, and the recording state is determined in steps 523 and S25. Therefore, if the recovery is not sufficient, proceed to step 5.
13, the pump 5 performs the recovery operation again, and when the recovery occurs, the process returns to step S3, the head unit 1 is positioned at the home position, the cap 9 is closed, and the system enters a standby state. Note that the test printing from step 519 onwards may or may not be performed.

FIGS. 5 and 6 show other embodiments of the invention;
For parts that can be constructed in the same manner as in the embodiment shown in the figure and the second figure, corresponding parts are given the same reference numerals. In this example,
A three-way valve 19 is provided in the middle of the suction tube 7 instead of the valve 12. Here, what is indicated by the reference numeral 20 is an atmospheric communication hole provided in the three-way valve 19. This three-way valve 19 switches the suction port 13 and the sub-tank 15 or the atmosphere to communicate with each other.

In this example as well, the configuration of the control system can be configured almost the same as that shown in FIG.

The operation of this embodiment will be described below using an example of a flowchart of the processing procedure shown in FIG.

First, immediately after the power is turned on, the three-way valve 1 is turned off in step 531.
9 communicates the atmosphere communication hole 20 with the ink suction port 13, and the cap 9 is closed in step S33. As a result, the temporary high pressure inside the cap 9 generated at the moment the cap 9 is closed can be released to the atmosphere. This prevents air from being taken in.

After the cap 9 is closed, in order to seal the inside of the cap 9 and prevent ink from increasing or sticking, the three-way valve 19 is switched in step 534 to communicate the sub-tank 15 and the ink suction port 13, and then step 534 is performed. S35
The system enters the image data standby state.

When the image data is input and the recording is started, the three-way valve 19 is switched in step 536 to connect the atmosphere communication hole 20 and the ink suction port 13 to the sub tank 1.
The inside of the sub-tank 15 is kept in a sealed state so that the ink level in the sub-tank 15 does not drop even during recording, that is, even when the cap 9 is open. Then, in step S37, the cap 9 is opened, and in step 539, recording processing is executed.

When recording is performed and a recording failure is confirmed in step 541, first in step S43 the head unit 1 is positioned at the home position with the ink suction port 13 communicating with the atmosphere via the three-way valve 19. , close the cap 9.

Next, in step S45, the three-way valve 19 is switched to 1.
The sub-tank 15 and the ink suction port 13 are communicated, and in step S47, the pump 5 is driven manually or automatically to start suction. When, for example, one second has passed after the start of this pumping (step 549), the three-way valve 19 is switched, and the ink suction port 13 is communicated with the atmosphere in step 551. After that, the suction operation by the pump 5 is continued for, for example, 4 seconds (step 553). This is because if the volume inside the cap 9 is large and the cap 9 is full of sucked ink, when the cap 9 is opened, In order to avoid this, air is sucked in from the ink suction port 13 during the last 4 seconds of pumping, since a large amount of ink leaks into the device or the area around the orifice 14 gets wet with ink, which tends to cause recording defects. This is done to empty the ink inside the cap 9.

After the bombing is completed, the cap 9 is opened in step S57, and test printing is performed in step 559. If the printing is good, the process returns to step S33 and enters the standby state again. If the condition has not been recovered, the process returns to step S43. and perform the recovery operation again.

According to the two embodiments described above, suction by the pump during the recovery operation is simultaneously performed from the ink suction port communicating with the ink tank as well as from the orifice, so that the ink in the orifice part becomes thickened or solidified. Even in such a case, thickened or stuck ink at the orifice portion within the cap can be washed away by the ink suctioned from the ink suction port. Therefore, extremely effective recovery operations are now possible, and the reliability of the device is improved even when the device is left unused for a long period of time, and a wide range of recording inks can be selected.

In the above explanation, an inkjet recording device using a suction pump as a recovery means has been described, but a recovery means is used in which recovery is performed by pushing ink out of an orifice using a pump that pressurizes the inside of an ink flow path. In this case, the ink suction port 1 provided in the cap
The part corresponding to 3 is used as an ink outlet that communicates with the pressurizing pump, and by letting ink flow out from the outlet and filling the inside of the cap with ink, thickening of the orifice part or fixed ink can be caused to flow out. Can be washed away with ink. Furthermore, in the two embodiments described above, the present invention was applied to an inkjet recording apparatus that performs ejection using a piezoelectric element, but the present invention can also be applied to an inkjet recording apparatus that uses other ejection energy generating elements, such as electrothermal transducers. It goes without saying that the invention is extremely effective and easy to apply.

[Effects of the Invention] As explained above, according to the present invention, ejection failures caused by thickening or sticking of ink at the orifice portion can be easily and reliably removed with a relatively simple configuration. Even later, recording inks can be selected from a wide range without impairing the reliability of the apparatus.

[Brief explanation of the drawing]

1 and 2 are a perspective view and a schematic cross-sectional view, respectively, showing a first embodiment of the inkjet recording apparatus of the present invention, and FIG. 3 shows an example of the configuration of a control system according to the first embodiment. FIG. 4 is a flowchart showing an example of the recording processing procedure according to the first embodiment including ejection recovery processing, and FIGS. 5 and 6 are a perspective view and a perspective view of the second embodiment of the present invention, respectively. A schematic cross-sectional view, FIG. 7 is a flowchart showing an example of the recording processing procedure according to the second embodiment, including the ejection recovery processing. DESCRIPTION OF SYMBOLS 1... Head unit, 2... Main tank, 3... Supply tube, 4... Recording paper, 5... Pump, 6... Pump suction tube, 7... Suction tube, 8... Waste liquid reservoir, 9... Cap, 10... Carriage, 11... Platen, 12... Valve, 13... Ink suction port, 14... Orifice, 15... Sub tank, 16... - Ink, 17... Ink channel, 18... Cylindrical piezoelectric element, 19... Three-way valve, 20... Atmospheric communication hole. Figure 11 Figure 6

Claims (1)

[Scope of Claims] 1) an ejection port that ejects ink onto a recording medium; a storage member that stores ink to be supplied to the ejection port; an ejection recovery means for introducing the ink; a first portion that can be joined to the ejection port during ejection recovery processing by the ejection recovery means and that receives ink discharged from the ejection port at the time of the joining; An inkjet recording apparatus comprising: a joining member having a second portion that receives ink introduced from the storage member; 2) The ejection recovery means includes a communication member that communicates the storage member and the second portion, and suctions the ink from the ejection port via the first portion and the communication member and the second portion. 2. The inkjet recording apparatus according to claim 1, further comprising a suction means for sucking ink from the storage member. 3) The inkjet recording apparatus according to claim 1 or 2, characterized in that an opening/closing means for opening and closing the flow of ink is provided in the middle of the communication member.